The bottom line: the entire ACA is upheld, with the exception that the federal government’s power to terminate states’ Medicaid funds is narrowly read.

In a key section, the ruling notes:

Our precedent demonstrates that Congress had the power to impose the exaction in Section 5000A under the taxing power, and that Section 5000A need not be read to do more than impose a tax. This is sufficient to sustain it.

In other words, the court ruled that the fact that the writers of the law called it a mandate rather than a tax is irrelevant, since it functions like a tax. No one questions Congress’s power to impose a tax.

SCOTUSblog’s Tom Goldstein expanded on that in an interview with msnbc. “As a technical matter you don’t have to buy health insurance if you’re willing to pay the tax,” Goldstein said. “You have to comply with the tax, it’s not an optional tax. The Supreme Court has said …the mandate is upheld under the taxing power and there is still a consequence for not complying with the mandate. The court didn’t throw out the mandate piece of this.”

Goldstein suggested the ruling will likely be seen broadly as legitimate and impartial. “The conservative Chief Justice of the U.S. Supreme Court upheld the President’s health care law,” he said. “The public can have a lot of confidence in this result.”

As TPM noted at the time, Roberts may have tipped his hand that he took this view of the mandate during oral arguments in March. “The idea that the mandate is something separate from whether you want to call it a penalty or tax just doesn’t seem to make much sense,” he declared at that time. “It’s a command. A mandate is a command. If there is nothing behind the command, it’s sort of, well what happens if you don’t file the mandate? And the answer is nothing. It seems very artificial to separate the punishment from the crime. … Why would you have a requirement that is completely toothless? You know, buy insurance or else. Or else what? Or else nothing.”

In a tweet, Rep. Nancy Pelosi, the House Democratic leader, called the ruling a “victory for the American people,” adding that “millions of American families and children will have certainty of health care benefits + affordable care.”

And Senate Majority Leader Harry Reid said on the Senate floor: “No longer will Americans live in fear of losing their health insurance because they lose a job. No longer will tens of millions of Americans rely on emergency room care or go without care entirely because they have no insurance at all.”

Meanwhile, RNC chair Reince Priebus tweeted: “Just elect Romney. We need full repeal.” And Speaker John Boehner echoed that, saying in a statement that the ruling “underscores the urgency of repealing this harmful law in its entirety.”

Republicans said the House would vote the week of July 9th on repealing the law. Mitt Romney has also said he’d repeal the law if elected.

The law’s supporters may not want to celebrate too hard just yet. Jonathan Turley, a law professor at George Washington, questioned whether the law can survive given that the court limited the federal government’s power to terminate Medicaid funds, effectively allowing states that oppose the law to opt out of it.

“This creates a ripple effect,” Turley said on msnbc. “A majority of states oppose this law. If they had an ability to opt out, they would. I don’t see how the health care law could survive if the pool is reduced by that amount. You need to force young people to buy health insurance since they’re not going to get sick as often and (having them in the pool) makes it more affordable.”

“The law is precarious in terms of staying an efficient system and being affordable,” Turley added.

Twenty-six states, most of them Republican leaning, sued to strike down the law, and many would presumably choose to opt out if allowed to do so.

If they did, they would likely have support from the GOP presidential nominee. A spokesman for the RNC, Sean Spicer, said Romney has made it clear that “states should do what’s best for their individual states.”

It’s also worth noting that the court rejected the administration’s argument that regulating inactivity falls under Congress’s power under the Commerce Clause, thereby severely limiting the future scope of Congress’s regulatory authority. In the majority opinion, Roberts wrote”

As expansive as our cases construing the scope of the commerce power have been, they all have one thing in common: They uniformly describe the power as reaching “activity.”

The individual mandate, however, does not regulate existing commercial activity. It instead compels individuals to become active in commerce by purchasing a product, on the ground that their failure to do so affects interstate commerce. Construing the Commerce Clause to permit Congress to regulate individuals precisely because they are doing nothing would open a new and potentially vast domain to congressional authority. Every day individuals do not do an infinite number of things. In some cases they decide not to do something; in others they simply fail to do it. Allowing Congress to justify federal regulation by pointing to the effect of inaction on commerce would bring countless decisions an individual could potentially make within the scope of federal regulation, and—under the Government’s theory—empower Congress to make those decisions for him.

That narrowing of Congress’s power under the Commerce Clause could have implications for future cases.